This invention relates to a rotary target assembly for an x-ray tube having a graphite disk secured to a rotary shaft, and a method of securing the graphite disk firmly to the rotary shaft to make such rotary target assembly.
Graphite target disks have been utilized for rotating anode x-ray tubes in the prior art designs. Advantages of their use have been described, for example, in the U.S. Pat. Nos. 4,276,493 and 4,481,655. However, the attachment of the graphite disk to a rotary shaft has been one of the major problems. The graphite target body became loose on the rotary shaft after being accelerated and decelerated many times during the operation.
An attempt to solve this problem has been disclosed in U.S. Pat. No. 4,736,400 claiming a method of attachment of the graphite disk and the rotary shaft by diffusing one portion of brazing material into the graphite disk and another portion into a flange being a part of the rotary shaft. With this method, however, the position of the graphite disk with respect to the flange may not be accurately controlled when the brazing material is melted.